Projection display systems provide a low-cost, high-performance alternative to expensive thin flat screen display systems, such as plasma and LCD direct view display systems. A projection display system with approximately the same screen size as a flat screen display system may cost a significant amount of money less than the flat screen display system. As the screen size increases, the cost advantage also increases. Furthermore, projection display systems may have optical advantages over flat screen display systems, such as a superior contrast ratio, smoother images, less visible picture elements, and so forth.
However, an advantage of flat screen display systems is their thinness (shallow cabinet depth). A flat screen display system may be as thin as a few inches, while a projection display system's cabinet may be several times thicker. Many consumers may select a flat screen display system over a projection display system, ignoring the projection display system's sometimes significant advantages, based solely on the flat screen display system's thinner profile and its ability to be mounted onto a vertical surface.
In a projection display system, such as a DMD-based projection display system, light from a light source is projected onto an array of light modulators (the DMD), which can, based on image data of an image being displayed, reflect the light away from or onto a display plane. Other micro-display technologies may modulate a light passing through the array of light modulators.
In order to produce an image of desired size, the modulated light in a projection display system must travel a predetermined distance in order to disperse sufficiently to create the properly sized image. The distance that the modulated light must travel may be a function of the optical characteristics of the optical system of the projection display system, such as the focal length of the lenses, desired image size, and so forth. Typically, the greater the distance that the modulated light must travel, the greater the cabinet depth.